react array functions code example

Example 1: react create array

const numbers = [1, 2, 3, 4, 5];
const doubled = numbers.map((number) => number * 2);console.log(doubled);

Example 2: react list based on state

import React, { Component } from 'react'; class App extends Component {  constructor(props) {    super(props);     this.state = {      list: [        { id: '1', age: 42 },        { id: '2', age: 33 },        { id: '3', age: 68 },      ],    };  }   onRemoveItem = id => {    this.setState(state => {      const list = state.list.filter(item => item.id !== id);       return {        list,      };    });  };   render() {    return (      <div>        <ul>          {this.state.list.map(item => (            <li key={item.id}>              The person is {item.age} years old.              <button                type="button"                onClick={() => this.onRemoveItem(item.id)}              >                Remove              </button>            </li>          ))}        </ul>      </div>    );  }} export default App;